PhD Arthur Decae 2010 - Ghent Ecology - Universiteit Gent

metatarsi I & II, but they may or may not extend onto the tibiae. In some species the typical
scopula-hairs are replaced by dense pubescence on the anterior tibiae, thus forming a distinct
pseudoscopula (Decae 1995). Spines: Descriptions of spine patterns are a major source of
confusion in Nemesia taxonomy. Owing to their conspicuous presence, spines and spine
patterns were used extensively as discriminative characters at the species level in early
literature. Usually these patterns were reported in the form of descriptions where figures
would have been less ambiguous. In more recent literature (Blasco 1986a; Cardoso 2000)
spine patterns in Nemesia have been regarded as taxonomically virtually useless, owing to
their extreme variability down to the individual level where different spine patterns are
frequently found on the left and right sides of a single spider. However, on certain faces of
some leg and palp segments, spine patterns may contain useful taxonomic information. Here
the prolateral spine formulae for all patellae are given (PSP, PSPvar), and those on patella III
and tibia III are figured (Figs. 17, 30, 37, 44, 51, 58, 65).
Leg IV: The relative lengths, measured
along the prolateral margin of the
metatarsus, tibia and femur, are of
diagnostic value at the species level and
are given in the ratios M4:T4:F4 (Fig. 5).
Metatarsal combs: The metatarsal
preening combs on legs III and IV that
were reported to be of diagnostic value in
Nemesia by Raven (1985: 96) are
unambiguously found only distally on
metatarsus IV in three Balearic species (N.
ibiza, N. randa and N. bristowei).
Spinnerets: The spinneret morphology of
Nemesia shows important, but so far
underrated, taxonomic characters for
species level taxonomy. The PMS may be
absent as in N. brauni (Fig.18), reduced,
having none or few apical spigots as in N.
bristowei (Fig. 31), or fully functional,
having spigots distributed over the distal
and ventral surface as in N. seldeni (Fig.
52). The PLS also show variation,
particularly in the spigot development on
the ventral surface of the basal segment.
Spigots may be absent, restricted to the
distal half of the segment (most species),
or distributed widely over the ventral
surface of the segment as in N. seldeni
(Fig. 52). Finally, the apical spigots on the
distal segment of the PLS may also show
important differences between species. All
species have a dense field of spigots at the apex of the PLS that are roughly arranged in
circular concentric rings of smaller spigots on the periphery around larger spigots more
centrally, with a few distinct "macro-spigots" in the centre. The number of macro-spigots can
be of diagnostic value. Spermathecae: The receptacles of the spermathecae provide a key
character for species identification in female Nemesia (see also Blasco 1986a). In general
three broad types of shape can be distinguished: unipartite with no distinct divisions between
Figs. 9-12 Nemesia brauni L. Koch, male. 9 body, dorsal; 10
distal end of right palp; retrolateral; 11 ditto, prolateral; 12 leg I
clasper, prolateral. Scale lines = 2mm (9), 1mm (10-12).